Fig. 1: Stimulus displays, task structure and response deadline algorithm.

a Illustration of the trial sequence during the main task. Trials started with a period of dot motion randomly drawn from a uniform distribution between 350–500 ms. Next, the dots moved coherently until participant response or the response deadline. Following the motion discrimination response, the dots stopped moving, became transparent (70% opacity) and a fixation cross appeared for 600 ms. Finally, the change-of-mind (CoM) display appeared for maximally 2000 ms, during which time participants rated their desire to change their mind about their motion discrimination response by moving the yellow marker along the continuous scale. b Task difficulty manipulations. During the coherent motion period, the coherence of the dot motion (i.e., the probability that the dots would move in the specified direction) and its angular offset from the criterion orientation were pseudo-randomly selected per trial to induce greater uncertainty (i.e., low coherence and/or small offset) or lesser uncertainty (i.e., high coherence and/or large offset). c Method for determining response deadlines during the main task. Participants completed a calibration task immediately prior to the main task to generate a per-participant response time distribution. The 25th and 90th percentiles of this distribution were then used as the short and long response deadlines during the coherent motion period of the main task, respectively. d Histogram of the short (aqua) and long (purple) response deadlines used during the main experimental task (N = 43).